Liquid crystal display apparatus

ABSTRACT

According to one embodiment, a liquid crystal display apparatus includes a display region including a plurality of display pixels arrayed in a matrix, an array substrate including a plurality of first electrodes which are arrayed in a matrix, second electrodes which are arranged on the same layer as a layer of the first electrodes and connect the first electrodes to each. other, and third electrodes which are arrayed in a matrix on the first electrodes and the second electrodes, a countersubstrate which is arranged to face the array substrate, and a liquid crystal layer which is interposed between the array substrate and the countersubstrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/679,757 filed Nov. 11, 2019, which is a continuation of U.S.application Ser. No. 15/589,492 filed May 8, 2017, which is based uponand claims the benefit of priority from prior Japanese PatentApplication No. 2011-136437, filed Jun. 20, 2011, the entire contents ofeach of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a liquid crystaldisplay apparatus.

BACKGROUND

Flat display apparatuses are currently undergoing active development,particularly liquid crystal displays, which are finding application invarious fields by dint of such desirable features as lightness,thinness, and low energy consumption. A liquid crystal display isrealized by confining a liquid crystal layer between paired substrates,the display producing an image as a result of the modulation factor oflight passing through the liquid crystal layer being controlled inaccordance with an electric field between a pixel electrode and a commonelectrode.

For liquid crystal display apparatuses, there are known a method ofcontrolling the liquid crystal alignment state by applying, to theliquid crystal layer, a longitudinal electric field in a directionalmost perpendicular to the substrate surfaces of the paired substrates,and a method of controlling the liquid crystal alignment state byapplying, to the liquid crystal layer, a transverse electric field(including even a fringe electric field) in a direction almost parallelto the surfaces of the paired substrates.

A liquid crystal display apparatus using a transverse electric fieldespecially receives attention in terms of a wider view angle. Atransverse electric field liquid crystal display apparatus in the IPS(In-Plane Switching) mode, FFS (Fringe Field Switching) mode, or thelike includes pixel electrodes and common electrodes formed on an arraysubstrate. Liquid crystal molecules are switched by a transverseelectric field almost parallel to the major surface of the arraysubstrate.

There is also proposed a liquid crystal display apparatus including atouch sensor which detects that a user's finger or pen tip has touchedthe display unit. The touch sensor is formed by further superposing asensor substrate including sensor electrodes on the display unit of theliquid crystal display apparatus or integrally forming sensor electrodeson one of paired substrates of the liquid crystal display apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view for explaining an example of thearrangement of a liquid crystal display apparatus according to anembodiment;

FIG. 2 is a sectional view showing an example of the section of theliquid crystal display apparatus shown in FIG. 1 taken along a lineII-II;

FIG. 3 is a plan view for explaining an example of the arrangement ofthe display region of the liquid crystal display apparatus shown in FIG.1 ;

FIG. 4 is a plan view for explaining an example of the arrangement ofcommon electrodes arranged in the display region of the liquid crystaldisplay apparatus shown in FIG. 1 ;

FIG. 5 is a plan view for explaining an example of the arrangement ofsensor electrodes arranged in the display region of the liquid crystaldisplay apparatus shown in FIG. 1 ;

FIG. 6 is a sectional view showing an example of a section taken along aline VI-VI shown in FIG. 3 ;

FIG. 7 is a plan view for explaining an example of the arrangement ofthe display region of a liquid crystal display apparatus of acomparative example;

FIG. 8 is a plan view for explaining an example of the arrangement ofcommon electrodes arranged in the display region of the liquid crystaldisplay apparatus of the comparative example; and

FIG. 9 is a sectional view showing an example of a section taken along aline IX-IX shown in FIG. 7 .

DETAILED DESCRIPTION

In general, according to one embodiment, a liquid crystal displayapparatus comprises a display region including a plurality of displaypixels arrayed in a matrix; an array substrate including a plurality offirst electrodes which are arrayed in a matrix, second electrodes whichare arranged on the same layer as a layer of the first electrodes andconnect the first electrodes to each other, and third electrodes whichare arrayed in a matrix on the first electrodes and the secondelectrodes; a countersubstrate which is arranged to face the arraysubstrate; and a liquid crystal layer which is interposed between thearray substrate and the countersubstrate.

A liquid crystal display apparatus according to an embodiment will nowbe described with reference to the drawings.

FIG. 1 schematically shows an example of the liquid crystal displayapparatus according to the embodiment. The liquid crystal displayapparatus includes a liquid cry al display panel including an arraysubstrate 110, a countersubstrate 120 which is arranged to face thearray substrate 110 at a predetermined interval, a liquid crystal layer70 (FIG. 2 ) interposed between the array substrate 110 and thecountersubstrate 120, and a display region 25 including display pixelsPX arrayed in a matrix, and a backlight unit 130 which illuminates theliquid crystal display panel from the back.

FIG. 2 shows an example of the section of the liquid crystal displaypanel shown in FIG. 1 taken along a line II-II. The liquid crystaldisplay apparatus according to the embodiment is a liquid crystaldisplay apparatus in the FFS mode in which the alignment state of theliquid crystal layer is controlled using a transverse electric field.

The array substrate 110 includes a transparent insulating substrate 10of glass or the like, pixel driving interconnections arranged on thetransparent insulating substrate 10, switching elements 14, insulatingfilms L1 and 50, a planarization film 20, common electrodes (first andsecond electrodes) 30, sensor electrodes (third electrodes) 40, pixelelectrodes (fourth. electrodes) 60, as alignment film (not shown), and adriving circuit. The pixel driving interconnections include scanninglines 11 running along rows in which the plurality of display pixels PXare arrayed, and signal lines 12 running along columns in which theplurality of display pixels PX are arrayed.

The driving circuit includes scanning line driving circuits ID which arearranged in a frame region around the display region 25 and drive theplurality of scanning lines 11, and a signal line driving circuit XDwhich drives the plurality of signal lines 12.

The scanning line driving circuits YD are arranged on two sides of thedisplay region 25 in a direction in which the scanning lines 11 run. Theplurality of scanning lines 11 running from the display region 25 areelectrically connected to the scanning line driving circuits YD. Theplurality of signal lines 12 running from the display region 25 areelectrically connected. to the signal line driving circuit XD.

A flexible board (not shown) is connected to the end of the arraysubstrate 110. A control signal and video signal are supplied from asignal source (not shown) to the scanning line driving circuits ID andsignal line driving circuit XD via the flexible board.

The scanning lines 11 run along the rows of the display pixels DXarrayed in a matrix in the display region 25. The signal lines 12 runalong the columns of the display pixels DX arrayed in a matrix in thedisplay region 25.

Each switching element 14 is arranged near a position where the scanningline 11 and signal line 12 cross each other. The switching element 14 isarranged on an undercoat layer (not shown) arranged on the transparentinsulating substrate 10. The switching element 14 includes a thin-filmtransistor including an amorphous silicon or polysilicon semiconductorlayer SC, gate electrode 14 b, source electrode 14 a, and drainelectrode 14 c.

A gate insulating film is arranged on the semiconductor layer SC of theswitching element 14. The gate electrode 14 b of the switching element14 is arranged on the gate insulating film. The source electrode 14 aand drain electrode 14 c of the switching element 14 are connected tothe semiconductor layer SC in a contact hole formed in the insulatingfilm L1.

The gate electrode 14 b of the switching element 14 is electricallyconnected to (or formed integrally with) the corresponding scanning line11. The source electrode 14 a of the switching element 14 iselectrically connected to (or formed integrally with) the correspondingsignal line 12. The drain electrode 14 c of the switching element iselectrically connected to the corresponding pixel electrode 60 incontact holes 21 and 51 (described later).

The scanning line driving circuit. YD drives the scanning line 11 toapply a voltage to the gate electrode 14 b of the switching element 14.Then, the source electrode 14 a and drain electrode 14 c are renderedconductive to turn on the switching element 14 for a predeterminedperiod. While the switching element 14 is on, a video signal is suppliedfrom the signal line 12 to the pixel electrode 60 via the switchingelement 14.

The planarization film 20 is arranged on the switching element 14. Inthe embodiment, the planarization film 20 is a transparent organicinsulating film, and the film thickness of the planarization film 20 isapproximately 3 μm. The planarization film 20 is arranged in the entiredisplay region 25 except for the contact holes 21. The contact hole 21is formed in the planarization film 20 on the drain electrode 14 c ofthe switching element 14 to electrically connect the pixel electrode 60(described later). The common electrodes 30 are arranged on theplanarization film 20.

FIG. 3 shows an example of the arrangement of the display region 25 ofthe array substrate 110. In FIG. 3 , the pixel electrodes 60 and sensorelectrodes 40 are partially omitted to represent the shape of the commonelectrodes 30.

In a color-display-type liquid crystal display apparatus, the pluralityof display pixels PX include color pixels of a plurality of types. Inthe embodiment, the plurality of display pixels PX include red displaypixels for displaying red, green display pixels for displaying green,and blue display pixels for displaying blue. One picture element isformed from color pixels of the three types, that is, red, green, andblue display pixels. In the display region 25, red display pixels, greendisplay pixels, and blue display pixels are periodically aligned in adirection in which the scanning lines 11 run, and color pixels of thesame type are aligned in a direction in which the signal lines 12 run.

FIG. 4 is a plan view for explaining an example of the arrangement ofthe common electrodes 30.

The common electrode 30 is a conductive oxide film, and is consisting ofa transparent electrode material such as indium tin oxide (ITO) orindium zinc oxide (IZO). The common electrodes 30 arranged at the end ofthe display region 25 extend to the frame region, and receive a commonvoltage from, for example, an external signal source via the flexibleboard.

The common electrodes 30 are formed using the same pattern by takingaccount of the overlay accuracy with the sensor electrodes 40 (describedlater). More specifically, the common electrodes 30 include a pluralityof first electrodes 30A which are arranged to face the plurality ofpixel electrodes 60, and second electrodes 30B which electricallyconnect the first electrodes 30A to each other. The first electrodes 30Aand second electrodes 30B are arranged on the same layer.

The first electrode 30A is arranged to face three pixel electrodes 60arranged in one picture element. The second electrode 30B is arrangedbelow the sensor electrode 40 (described later) between the firstelectrodes 30A. The width W2 of the second electrode 30B is almost equalto the width W1 of the sensor electrode 40, and is about 5 μm. The widthW2 of the second electrode 30B is a width in a direction in which thesignal line 12 of an electrode extending almost parallel to the scanningline 11 runs, and a width in a direction in which the scanning line 11of an electrode extending almost parallel to the signal line 12 runs.

A connection electrode 31 of the same material as the common electrode30 is arranged in each contact hole 21. The drain electrode 14 c of theswitching element 14 and the connection electrode 31 are electricallyconnected in the contact hole 21.

FIG. 5 is a plan view for explaining an example of the arrangement ofthe sensor electrodes 40. In FIG. 5 , broken lines represent the patternshapes of the common electrodes 30 and connection electrodes 31. Thesensor electrodes 40 are arranged on the common electrodes 30. Thesensor electrode 40 is, for example, a multilayered electrode ofaluminum and molybdenum. The sensor electrodes 40 are arrayed in amatrix, including first sensors extending almost parallel to a directionin which the scanning lines 11 run, and second sensors extending almostparallel to a direction in which the signal lines 12 run. The sensorelectrodes 40 electrically connect the plurality or common electrodes30. In the embodiment, the width W1 of the second sensor in a directionin which the scanning lines 11 run, and the width W1 of the first sensorin a direction in which the signal lines 12 run are about 5 μm.

In the embodiment, each sensor electrode 40 extending almost parallel tothe signal line 12 is arranged on the signal line 12 between colorpixels of predetermined two types out of red, green, and blue displaypixels which are arranged periodically in a direction in which thescanning lines 11 run in the display region 25.

FIG. 6 shows an example of the section of the array substrate 110 takenalong a line VI-VI in FIG. 3 . The sensor electrode 40 is desirablyarranged at a flat portion free from a step on the common electrode 30in the display region 25. In the embodiment, the sensor electrodes 40are arranged on the first electrode 30A and second electrode 30B of thecommon electrode 30.

The sensor electrodes 40 extend to the frame region, and areelectrically connected to, for example, an external sensor circuit (notshown). When detecting a touch position on the liquid crystal displayapparatus according to the embodiment, the sensor circuit supplies asignal of a predetermined waveform to the sensor electrode 40. Themagnitude of a capacitance generated between the user's fingertip or astylus tip and the sensor electrode 40 changes depending on the distancebetween the fingertip or the like and the sensor electrode 40. Thesensor circuit detects, from the output waveform of a signal output fromthe sensor electrode 40, a change in the potential of the sensorelectrode 40 upon the change in capacitance between the fingertip or thelike and the sensor electrode 40, thereby detecting a coordinateposition of the sensor electrode 40 that corresponds to the positiontouched with the fingertip of the user, stylus tip, or the like.

FIG. 7 schematically shows an example of the arrangement of the displayregion of a liquid crystal display apparatus of a comparative example.

FIG. 8 is a plan view for explaining an example of the arrangement of acommon electrode 30 and connection electrodes 31 in the liquid crystaldisplay apparatus of the comparative example. In the liquid crystaldisplay apparatus of the comparative example, the common electrode 30includes a plurality of island-like first electrodes 30A. Morespecifically, in the liquid crystal display apparatus of the comparativeexample, the common electrode 30 does not include the second electrodes30B which connect the first electrodes 30A to each other. Instead, thesensor electrodes 40 are arranged on the common electrode 30 toelectrically connect the island-like first electrodes 30A. Byelectrically connecting the island-like first electrodes 30A by thesensor electrodes 40, the first electrodes 30A arranged in the displayregion 25 are set to almost the same potential. If an integral commonelectrode is arranged in the entire display region 25, the resistance ofthe common electrode increases and display nonuniformity occurs,degrading the display quality. However, when the common electrode 30 isformed from the plurality of island-like first electrodes 30A,generation of display nonuniformity can be avoided, providing ahigh-display-quality liquid crystal display apparatus.

FIG. 9 shows an example of a section taken along a line IX-IX in FIG. 7.

However, when the common electrode 30 is formed from the plurality ofisland-like first electrodes 30A, as described above, the sensorelectrodes 40 arranged on the common electrode 30 are arranged acrossthe pattern ends of the first electrodes 30A. The electrode may bedisconnected on a step formed at the pattern end of the first electrode30A, or a void may be formed, increasing the resistance of the sensorelectrode 40.

To the contrary, in the liquid crystal display apparatus according tothe embodiment, the second electrode 30B is formed below the sensorelectrode 40 between the first electrodes 30A. Thus, the sensorelectrode 40 is not arranged across the pattern end of the firstelectrode 30A. In the liquid crystal display apparatus according to theembodiment, the sensor electrode 40 is not disconnected and no void isformed, avoiding an increase in the resistance of the sensor electrode40. That is, the embodiment can provide a liquid crystal displayapparatus including low-resistance, high-quality sensor electrodes.

The insulating film 50 is arranged on the sensor electrodes 40. Theinsulating film 50 is, for example, an inorganic insulating film, andincludes the contact holes 51 each for electrically connecting the pixelelectrode 60 and connection electrode 31.

The pixel electrodes 60 are arranged on the insulating film 50, andelectrically connected to the connection electrodes 31 in the contactholes 51. The pixel electrode 60 is a conductive oxide film, and isconsisting of a transparent electrode material such as ITO or IZO. Thealignment film (not shown) is arranged on the pixel electrodes 60.

As shown in FIG. 3 , the pixel electrode 60 includes slits 60S extendingalmost parallel to each other. In the embodiment, the plurality of slits60S extend almost parallel to a direction in which the signal lines 12run.

The alignment state of the liquid crystal layer 70 is controlled by anelectric field generated between the pixel electrode 60 and the commonelectrode 30 or between the end of the pixel electrode 60 and the sensorelectrode 40. By forming the slits 603 in the pixel electrode 60, anelectric field is generated between the pixel electrode 60 and thecommon electrode 30 even at the center of the display pixel PX, and thealignment state of the liquid crystal layer 70 can be controlled.

The countersubstrate 120 includes a transparent insulating substrate 28of glass or the like, a transparent resin planarization film 29, aplurality of colored layers, and an alignment film (not shown).

The plurality of colored. layers are organic insulating films, andinclude a first colored layer 24 a, second colored. layer 24 b, andthird colored layer 24 c each of which is colored with a resist of oneof red (R), green (G), and blue (B), and a fourth colored layer 27 a andfifth colored layers 27 b in black.

The red first colored layer 24 a is arranged in a red display pixel, thegreen second colored layer 24 b is arranged in a green display pixel,and the blue third colored layer 24 c is arranged in a blue displaypixel. The fourth colored layer 27 a is a light shielding layer which isarranged around the display region 25 and prevents transmission of lightin the frame region. The fifth colored layers 27 b are light shieldinglayers which are arrayed in a matrix at positions where they face thescanning lines 11 and signal lines 12 of the array substrate 110, andprevent transmission of light between the display pixels PX.

The array substrate 110 and countersubstrate 120 are arranged so thattheir alignment films face each other, and are fixed by a sealing agent26. Columnar spacers 22 are interposed between the array substrate 110and the countersubstrate 120. The columnar spacers 22 keep constant thedistance between the array substrate 110 and the countersubstrate 120.In the embodiment, the height of the columnar spacer 22 is arbitrarilycontrolled to fall within a range of 2 μm to 6 μm.

The liquid crystal layer 70 is arranged in a region defined by the arraysubstrate 110, countersubstrate 120, and sealing agent 26.

Polarizing plates (not shown.) are respectively arranged on surfaces ofthe array substrate 110 and countersubstrate 120 that are opposite tothe liquid crystal layer 70.

Next, a method of manufacturing the liquid crystal display apparatusaccording to the embodiment will be exemplified.

First, a method of forming the array substrate 110 will be explained.Film formation and patterning are repeated on the first transparentinsulating substrate for cutting out a plurality of array substrates110, thereby forming switching elements 14, scanning lines 11, signallines 12, an insulating film L1, and other switching elements andvarious interconnections on the array substrate 110.

Then, an exposure resist is applied, exposed, and developed, yielding aplanarization film 20 in the form of a transparent organic insulatingfilm. At this time, the exposure resist is applied to the entire displayregion 25 and frame region. The embodiment employs a photocurableexposure resist. The photoresist is exposed via an exposure mask,developed, and formed into a planarization film 20 of a predeterminedpattern having contact holes 21.

A transparent electrode material such as ITO is formed on theplanarization film 20, and an exposure resist is further applied to thetransparent electrode material. The exposure resist is exposed,developed, and patterned into a predetermined pattern of the connectionelectrodes 31 and common electrodes 30. The transparent electrodematerial is patterned by etching, and the exposure resist is removed,forming the common electrodes 30 of the predetermined pattern.

Film formation and patterning of molybdenum are performed on the commonelectrodes 30, film formation and patterning of aluminum are performed,and film formation and patterning of molybdenum are further performed.Electrode patterns of aluminum and molybdenum are formed a plurality oftimes on the first electrodes 30A and second electrodes 30B of thecommon electrodes 30, thereby forming sensor electrodes 40.

An exposure resist is applied to the sensor electrodes 40, exposed, anddeveloped, forming an. insulating film 50 having contact holes 51. Afilm of a transparent electrode material such as ITO is formed on theinsulating film 50 and patterned into a predetermined pattern havingslits 60S, thereby forming pixel electrodes 60. An alignment film havingundergone rubbing processing in a predetermined direction is formed onthe surfaces of the pixel electrodes 60.

Next, a method of forming the countersubstrate 120 will be explained. Acolored exposure resist is repetitively applied, exposed, and developedon the second transparent insulating substrate for cutting out aplurality of countersubstrates 120, forming a first colored layer 24 a,second colored layer 24 b, third colored layer 24 c, fourth coloredlayer 27 a, and fifth colored layer 27 b. A transparent resin materialserving as the transparent resin planarization film 29 is applied to theplurality of colored layers, and patterned into a predetermined pattern,forming a transparent resin planarization film 29. Then, an alignmentfilm having undergone rubbing processing in a predetermined direction isformed on the surface of the transparent resin planarization film 29.

Columnar spacers 22 are formed by applying, for example, a resinmaterial to the first transparent insulating substrate or secondtransparent insulating substrate, and patterning it into a predeterminedpattern.

Subsequently, a sealing agent 26 in the form of, for example, anultraviolet curable resin is applied to the first transparent insulatingsubstrate or second transparent insulating substrate to surround thedisplay region 25. The transparent insulating substrate serving as aplurality of array substrates 110 and the transparent insulatingsubstrate serving as a plurality of countersubstrates 120 are aligned toface each other. The sealing agent 26 is irradiated with ultravioletrays and cured, fixing the transparent insulating substrates.

A liquid crystal material may be injected into the display region 25from an injection port formed in the sealing agent 26. Alternatively,before adhering the first and second transparent insulating substrates,a liquid crystal material may be dropped into a region defined by thesealing agent 26. When a liquid crystal material is injected from theinjection port, the injection port is sealed with a sealing agent afterinjection, forming a liquid crystal layer 70. When a liquid crystalmaterial is dropped, the first and second transparent insulatingsubstrates are adhered after dropping, forming a liquid crystal layer70.

While the first and second transparent insulating substrates are adheredto each other, a plurality of array substrates 110, and portions of thesecond transparent insulating substrate that face the array substrates110 are cut out. Further, the second transparent insulating substrate iscut into the countersubstrate 120.

Thereafter, polarizing plates are arranged on surfaces of the arraysubstrate 110 and countersubstrate 120 that are opposite to the liquidcrystal layer 70, forming a liquid crystal display apparatus.

When sensor electrodes are integrally formed on one of pairedsubstrates, a step is formed at the pattern end of a conductive layer orthe like arranged below the sensor electrode, and the sensor electrodearranged on the conductive layer may be disconnected or a void may beformed. If the sensor electrode is disconnected or a void is formed, theresistance of the sensor electrode increases, decreasing the touchposition detection accuracy or generating a short circuit.

As described above, in the liquid crystal display apparatus according tothe embodiment, the common electrode 30 and sensor electrode 40 areformed to have the same potential. In addition, the second electrode 30Bis arranged below the sensor electrode 40 between the first electrodes30A of the common electrodes 30. Hence, the sensor electrode 40 is notarranged across a step at the pattern end of the first electrode 30A,preventing a disconnection of the sensor electrode 40 or formation of avoid. The embodiment can therefore provide a liquid crystal displayapparatus which includes low-resistance, high-quality sensor electrodesand has high touch position detection sensitivity.

Note that the width W2 of the second electrode 30B in a direction almostperpendicular to a direction in which the second electrode 30B extendsbetween the first electrodes 30A is almost equal to the width W1 of thefirst sensor in the column direction and the width W1 of the secondsensor in the row direction. However, the same effects as those of theabove-described embodiment can be obtained as long as the width W2 ofthe second electrode 30B is equal to or larger than the width W1 of thefirst and second sensors. When the width W2 of the second electrode 30Bis increased, it should be adjusted to neither increase the resistanceof the common electrode 30 nor cause display nonuniformity.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprising: a plurality ofpixels; switching elements including a first switching element and asecond switching element, and located in the plurality of pixels; signallines electrically connected to the switching elements; pixel electrodesincluding a first pixel electrode electrically connected to the firstswitching element in a first contact portion and a second pixelelectrode electrically connected to the second switching element in asecond contact portion; a common electrode opposed to the first pixelelectrode and the second pixel electrode; and a metal wiring parallel toone of the signal lines, the common electrode including a slit whichextends in an extending direction of the signal line and overlaps one ofthe signal lines, and an opening where the first contact portion and thesecond contact portion are located, the metal wiring being in directcontact with the common electrode, being connected to the commonelectrode and being located so that the metal wiring does not overlapthe opening, a portion of the common electrode being between the metalwiring and the signal line.
 2. The display device according to claim 1,wherein the metal wiring includes a portion that does not overlap theslit.
 3. The display device according to claim 1, wherein the metalwiring is located on the common electrode, and is in contact with thecommon electrode.
 4. The display device according to claim 1, whereinthe common electrode is located below the metal wiring, and in theextending direction, a width of the metal wiring is less than a width ofthe common electrode at a position opposed to the metal wiring.
 5. Thedisplay device according to claim 1, wherein one of the signal lines isbetween the first contact portion and the second contact portion, andone of the signal lines overlaps the slit and the opening.
 6. Thedisplay device according to claim 1, wherein the slit and the openingare continuous with each other.
 7. The display device according to claim1, wherein the slit is between the first pixel electrode and the secondpixel electrode.
 8. The display device according to claim 1, wherein theswitching elements include a third switching element, the pixelelectrodes include a third pixel electrode electrically connected to thethird switching element in a third contact portion, the third contactportion is adjacent to the second contact portion in a directioncrossing the extending direction of the signal line, and the commonelectrode is between the second contact portion and the third contactportion.
 9. The display device according to claim 8, wherein the commonelectrode includes another opening, the third contact portion is locatedin the another opening, and the another opening and the slit are notcontinuous with each other.
 10. The display device according to claim 9,wherein the metal wiring does not overlap the another opening.